The present invention relates to a method of remotely controlling a plurality of bidirectionally variable functions by means of repeatedly transmitted bursts of pulse signals.
The invention also relates to a transmit-receive device for us in the said method, which device includes at the transmitter end a keyboard and a clock signal generator and at the receiver end a binary counter which cooperates with a binary/decimal decoder circuit.
The invention relates in particular but not exclusively to devices which enable a user to remotely and wirelessly control various settings of apparatuses such, for example, as television receivers or hi-fi installations by means of a small-size operating case.
Devices of this type are known for remotely controlling, for example, the sound volume, the contrast and the brightness of a television receiver. If further functions such, for example, as channel selection, color saturation, switch-on and switch-off etc. are also to be influenced, the large number of items of information to be transmitted requires complicated modulation of a current or an acoustic, optical or radio-frequency carrier. The receiver also will then become complex, because a large number of resonant filters must be used which must be tuned to modulation frequencies corresponding to the various functions.
For example, remote control of the afore-mentioned six functions requires twelve items of information to be transmitted, because each function must be variable in two directions.
Moreover, permanent modulation of the carrier when transmitting a remote control instruction requires an appreciable expenditure of energy so that the control case must be provided with a battery of a capacity sufficient for use during a reasonable time.